Patent GB-315903-A (GB)
Title: Improvements in or relating to gramophones
IPC: G11B3/00
Filed: 1928-04-17
Abstract: 315,903. Hall & Co., Ltd., W., and King, G. B. April 17, 1928. Securing tools to tool-arms.- A device for gripping a needle to the stylus-bar comprises a member movable at right-angles to the needle-receiving member and operable by means which apply equal and opposite forces to the receiving and gripping members respectively. The device is specially suitable to machines supplied with needles from a magazine, the gripper release being effected by pivoted levers which may be carried by the sound-box or on a fixed part of the machine and are arranged for self-centring. The device may hold the needle in a triangular socket or in an open V- groove and, on releasing, acts first to force the used needle out of the V so as to ensure its fall from the stylus-bar. The tone-arm is constructed and guided so that on its return movement, after playing, the sound-box is carried to a position in which the gripper device is released. In Fig. 10 the needle is shown retained in a triangular socket 15 by a sliding spring-pressed pin 17, and it is released by pivoted levers engaging respectively the head of the pin 17 and the opposite side of the soclet. In a modification, Fig. 18, the needle is held in an open V-groove on the side of a projection 160 from the stylus-bar 163 by a spring-pressed pin 164 carried from a pivot 166 and passing freely through the projection 160. In other arrangements, the gripper is in the form of a stirrup sliding on, or guided by, the projection 160 and provided with lugs or pins to engage the needle when moved at right-angles thereto. In one method of operating the gripper, the sound box is fitted with pivoted bevel-nosed levers 30, 31, Fig. 8, and the tone-arm is jointed and so guided in its return movement after playing that the sound-box is carried opposite a fixed structure, which may carry a needle magazine, and the nose ends of the levers 30, 31 ride against rolls 41, Fig. 5, whereby the gripper pin 17 is moved against its spring to press the needle from the V-groove and allow it to fall from the holder. The rolls 41 are mounted on a sliding frame 42, or the pivots of the levers 30, 31 are movable, to permit self-centring. In another arrangement, the pivoted gripper-operating levers 228, Fig. 15, on the sound-box 190 are actuated by sliding members 211, 213 on an arm 186 movable about the tone-arm mounting when the sound-box is moved against it, and in this movement the sound-box is rotated on the end of the tone-arm against a spring 192 to bring thee needle socket vertical by the movement of a slide on the arm engaging a lug 199 on the sound-box, which slide is moved through lever 201 and rod 203 from a fixed cam 205. During this action, another fixed cam 225 acts through a lever 222 and Bowden wire mechanism 220 to slide the members 211, 213 so as to actuate the gripper releasing levers 228. In a modified arrangement, the pivoted gripper-releasing levers 133, 134, Fig. 14, are carried by the arm 129 which is pivoted on the tone-arm mounting and moves with the tonearm during the latter part of the tone-arm return movement. During this movement, bowls 138 on the rear ends of the gripper-releasing levers 133, 134 ride along cam surfaces 139, 140 of a fixed slotted plate 141 to effect release of the gripper. Specification 315,737; and 324,397, [Class 18, Boxes &c.], are referred to.